http://www1.autozone.com/servlet/UiB...7EFIRING+ORDER

This is for a 96 Bronco, so it shoud be similar. I hope that link works. If it doesn't, just go on Autozone.com and look into the Repair info section. It will give you the specs on the firing order.

 

Thanks for all your help, guys. I checked the firing order and that was a good idea. The 5 and 6 wires were reversed. Reversing that fixed the backfiring and it will now drive. Now, the problem becomes that it is still running like crap. I have no power and it accelerates super roughly. I don't think the Y pipe is on well enough because it sounds like it is leaking pretty badly. Would that cause me problems? Thanks.

 

Have you reset the computer? maybe you cracked a spark plug?

 

How do you go about resetting the computer? Do spark plugs normally crack? If that is the case, I am paying someone to do it because there is no way in heck I am going to be able to get those plugs out without removing the headers again.

 

Just unplug the battery. I normally let it sit a half hour unplugged. The plugs can crack if there was too much force used to tighten them, or if they were somehow banged. Whenever adding headers, its always a good idea to get a fresh set of plugs and wires.


Rich

 

I did put new plugs in before installing the headers. I am not going to be happy about having to remove the headers and plugs again. Would the crack be visible with them in the block? The battery was unplugged while installing the headers so that should not be the problem.

 

The only other thing I can think of, is maybe your leak is so bad it's confusing the O2 sensor. If it's runs fine cold, and then bad when it's hot then it could be the O2 sensor.

 

It runs like crap all the time

 

You might want to post youre running issues in the 351w forum. I know there are alot of guys there that dont have broncos, but do have knowledge of the 351. They might be able to tell you something we havent. Have you pulled any codes? I guess you could have a bad sensor that is causing the running issues. Also, you wont necessarily see that you cracked a plug. Do you have a wire loom? Have you checked to make sure youre wires arent crossing?


Rich

 

If I pull the plugs out, would I be able to see the crack? What exactly is a wire loom? Having the wires crossed could cause issues? They should not be able to touch each other at all or what? Thanks.

 

A wire loom keeps all the wires from touching. If you have old crappie wires you could have a cross fire problem. Try misting the wires with water at night with the engine running if they are cross firing you will see arcs, it's kinda cool actually. The 351 is not as bad about cross fires as the 302 due to the firing order but it can happen.

 

I just thought of this and it maybe way out there but if you damaged the air diverter valve so it constantly dumped air in the cat it might have melted the cat. I'm just shooting in the dark here.

 

Well, I went out and misted the wires and ran it in the dark. Sure enough, the front plug on the passenger side was sparking away. It looks like the spark is coming from between the plug boot and plug maybe? It appears as sort of a ring of flash around the base of the plug. Does that make sense? What would cause that and what is the fix? Thanks.

 

sounds like you cracked that plug insulator

 

So basically I just need to replace that plug?